Chemotherapy Better In Smaller Doses

Prostate cancer patients whose cancer has not improved through chemotherapy may have a new, more effective medication alternative.

Scientists at the University of Georgia gave lower, more frequent doses of a chemotherapy agent to mice injected with human prostate cancer tumors. Frequent doses of less toxic amounts of chemotherapy, known as metronomic dosing, altered and improved the way the drug behaved and gave hope for new uses in prostate cancer treatment. 

The U.S. Food and Drug Administration (FDA)  approved chemotherapy drug Hycamtin (topotecan hydrochloride) is commonly used for cervical and ovarian cancer patients who have not recovered, or whose cancer has returned, despite chemotherapy. 

Special dosing of Hycamtin may become a new treatment for prostate cancer.

The study's co-author, Dr. Robert D. Arnold, suggests metronomic dosing of Hycamtin limits new blood vessels from developing thus decreasing the tumor's size. In mice, it slowed tumor growth as well as decreased harmful side effects.

Metronomic dosing of Hycamtin may also alter what type of genes are active in the tumor, according to Dr. Arnold.

These results could prove beneficial for late-stage prostate cancer treatments because the doses are much lower than what would be considered toxic to healthy cells in the body and decreasing the risk of serious side effects.

Hycamtin, in large doses, kills cancerous tumors by deactivating enzymes used for cell growth. This could have negative side effects such as hair and bone loss.

New clinical trials for Hycamtin's effects on prostate cancer could soon occur. The effects of metronomic dosing for humans is in the early phases of research.

This study will be published in Vol 12, Issue 7 of Cancer Biology and Therapy.